Propeller blade preloading and fluid transfer mechanism



Dec. 30, 1952 E. M. FRANKLAND PROPELLER BLADE PRELOADING AND FLUID TRANSFER MECHANISM Filed March 14, 1950 2 SHEETS-SHEET 1 INVENTOR E 61''] M Frank/B170. BY H ATTORNEY Dec. 30, I952 E. M. FRANKLAND PROPELLER BLADE PRELOADING AND FLUID TRANSFER MECHANISM Filed March 14, 1950 2 SHEETS-SHEET 2 m I E W mum W INVENTOR B 1? ar/MEwnK/anzi vv w 4? M ATTORNEY Patented Dec. 30, 1952 PROPELLER BLADE PRELOADING AND.

TRANSFER MECHANISM .Earl M. Frankl'and, Manchester, Oonn., assignor to United Aircraft Corporation, East. Hartford,

Conn., a corporation of Delaware Application March 14, 1950', Serial No. 149,545

8 Claims (01. 170-46033) This invention relates to hydraulically operated variablepitch propellers and more specifically to blade preloading and fluid transfer mechanisms for propellers having hydraulic pitch changing motors mounted in the blades.

It is an objectv of this invention to provide a combined fluid transfer and preload mechanism for variable pitch propeller blades having hydraulic pitch changing motors carried in the blades which motors receive fluid under pressure from a source carried by thehub of the propeller or carried externally thereof. Another object of this invention is to provid a mechanism of the'type described including a fluid transfer unit communicating with the hub and the hydraulic motor in the blade which unit may be installed in either of two positions for use in either propeller of counter-rotating or dual rotation propellers.

A further object'of this invention is to provide a. transfer unit as described herein which engages the hub, and the fluid motor in the propeller blade and includes a preloadingmember engaging the motor for loading the blade and its retention bearin s: in, an, outboard direction.

These and other objects of this invention will become readily apparent from the following. detail description of the drawings in which:

. Fig}. 1 is a partial cross-sectional view of a propeller including a schematic illustration of the hydraulic control and supply units which provide iiuidunder pressure to. the blades;

Fig. 2 is a cross-sectional view taken along the line2--2 of Fig. 1;

Figs. 3 and 1 are detailed views of the fluid transfer unit; and,

. Figs. 5 and 6 are detailed, views of the preloading nut;

Figs. '7 and 8 illustrate the propeller pitch lock cylinder including the portions thereon which engageably lock the preloading nut.

Referring to Fig. l, a propeller assembly is shown having a main hub portion l0 and integral blade receiving socket l2 and aipropeller'blade I l-mounted for pitch changing movement within the socket l2.

r The blade M includes ashank I6 having integral ball bearing races It on the outer periphery thereof which cooperate with similar races integrally formed on the inner periphery of the hub socket 12 so as to receive a plurality of balls 22 for retaining the blade against centrifugal forces within the socket I2. A plurality of passages are provided in the socket l2 in order to permit insertion of the balls-ZZ-and these passages may be provided with closure members, as for example theplugs 32.

The propeller is rotated by a driving element, for example the gear ill, which gear also may engage a bevel gear 42 for rotating a centrifugal governor generally indicated at 44. Governors of this type are well-known in the art 'a'ndmay be provided with a pilot valve t6 which is reciprocably controlled by the fiyweights 43. -The pilot valve 45 is utilized to control fluid under pressure from the hydraulic system comprising a fluid reservoir 50, a pump 52 and a relief valve 54.

It is apparent then that movements of the pilot valve 415' will direct fluid under pressure to either of the lines 58 or 50 in order to vary the pitch of the propeller blades in a manner to be described hereinafter. In the event fluid under pressure fixed to the blade It against relative rotation about the blade axis by means of splines "M (Fig. 1). The Outer vane motor portion 12 includes a flange 15 which engages the lowermost portion of the blade shank I5 and carries along a portion of its periphery a gear segment it adapted to engage a blade synchronizing gear I! t insure simultaneous pitch change of all the blades in the usual manner. The vane motor 10 also includes a fixed inner portion l8 having vanes 8'0 which sealably engaged the outer vane motor portion 12. The inner portion 18 is fixed to the main hub portion It) by means of a spline connection 84 (Fig. 1).

As seen in Fig. 2, fluid under pressure may be directed into the chamber 98 by means of passages 92 or into the chambers 94 by means of passages 96 in order to cause rotation of the outer vane motor portion '12 and the propeller blade [4 in either pitch changing direction. As better seen in Fig. 1, the passages 82 which lead to the chambers are in fluid communication with the passage 96 in the inner vane motor portion 18 While the passages 96 leading to the vane motor chambers 94 communicate with the passage 88 in the inner vane motor portion 18.

As seen in Fig. 1, fluid under pressure, whichis directed to the propeller from the hydraulic'control system via the lines 58 and 60, flows through the passages I00 and I02 in the main hub portion (0 into the annular passages IE4 and Hit formed on the outer periphery of a header ring H in fluid sealingengagement with the hub portion I0.

In order to'provide a fluid tight transfer of high pressure fluid from the header ring into the vane motor a fluid transfer unit I20 is located cen-" trally of the inner vane motor portion 18 in sealing engagement with a circular bore I22. its better seen in Figs. 3 and 4, the fluid transfer unit I20 comprises a stem I24 having a threaded base I26. The transfer unit I20 also includes two diametrically opposed passages I30 and I32 which.v

are disposed substantially axially of the base I26 and the stem I24.

mediate the axial ends of'the transfer unit I20 in a radial port I36. The outboard end of the" The passage I30 is a through passage while the passage I32 terminates inter-.-

stem I24 carries a slot I38 which cooperates with a dowel I40 (Fig. 1) fixed in the inner vane motor portion I8 to maintain the transfer unit in a posi tion fixed against relative rotation. The dowel I40 acts as a lock and locator device since it is spaced from the longitudinal axis of the transfer unit.

a As shown in Fig. 1, the passage I30 in the transfer unit I communicates with the passage 98 in the inner vane motor portion 18 while the pas sage I32 communicates with the passage 96 in this same vane motor portion. It is then apparent that if it is desirable to reverse the pitch changin direction of the vane motor and the propeller blade in response to the fluid controlling direc tions of the governor and hydraulic system, the fluid transfer unit I20 may be withdrawn from the bore I22 rotated 180 and then reinserted in engaging and rotatably locked position with the dowel I40. In this manner, in the event that dual rotation propellers are utilized, the same fluid transfer unit can be used for both propellers The 2,462,932-Pitch Changing Mechanism, issued March 1, 1949, to John E. Anderson.

In order to seal the fluid transfer unit I20 against the main hub portion I0 and in order to properly preload the blade retention bearings 22, a preloading nut I is threaded onto the flanged portion I26 of the fluid transfer unit I20. Asthe preload nut I50 is rotated onto the threaded-flanged portion I26 of the fluid transfer unit I20 (in an outboard direction) its upper surface portion I54 (Figs. 5 and 6) abuts the lowermost surface I56 of the inner vane motor portion 18. As the nut I50 is tightened against surface I56 the fluid transfer unit I20 is forced inboard in positive engagement with the main hub portion I0 while the vane motor is forced in an outboard direction to the extent that the flange 15 on the outer periphery of the vane motor outer portion I2 will force the blade shank I6 in an outboard direction so as to preload the balls 22.

When the preload force has been properly adjusted by rotation of the preload nut I50, it is locked in position by means of a pitch lock cylinder I80 which carries a plurality of teeth I82 (better seen in Figs. '7 and 8) for engagement with one of the serrations I 84 of the preload nut I50.

The pitch lock cylinder I8!) is fastened by means of bolts (not shown) to the hub main portion I0 and encloses a pitch lock piston I90 (Fig.

1) which does not form a specific part of this invention; however, it should suflice tomention that the pitch lock piston I includes ratchet type teeth I92 which engage similar teeth on the blade synchronizing gear 11 for locking the blades against pitch changing movements. Fluid under pressure normally keeps the piston in an aft disengaged position against the bias of a plurality of springs I94. Thus a loss of pressure acting on the pitch lock piston will permit the springs I94 to force the piston I90 into a lock engaging position. The pitch lock system may be of the type more fully described and claimed in patent application Serial No. 128,955, filed November 23, 1949, by John E. Anderson and patent application Serial No. 129,082, filed November 23, 1949, by Erle Martin and Thomas B. Rhines.

It is therefore apparent that as a result of this invention a combination fluid transfer unit and blade preload mechanism has been provided for providing a fluid tight communication between the propeller hub and pitch changing motors carried in the blades.

Also, as a result of this invention, a novel. simple and interchangeable mechanism has been provided whereby the unit is adaptable for use in single propellers or in either propeller of dual rotation assembly.

Although only one embodiment of this invention has been illustrated or described herein, it is apparent that various changes and modifications may be made in the construction and arrangement of the various parts without departing from the scope of this novel concept.

What it is desired by Letters Patent is:

1. In a propeller, a hub including a blade receiving socket, a propeller blade positioned in said socket for pitch changing movements, anti-friction bearing interposed between said blade and socket for retaining said blade therein, means responsive to fluid under pressure for varying the pitch of said blade comprising a fluid motor positioned in said blade having fluid receiving passages therein, said motor including a supporting member engaging said blade to prevent relative movement of the motor in an outboard direction, high pressure and drain pressure fluid conducting passages in said hub, and a fluid transfer member positioned axially of said motor for interconnecting the passages in said hub with the passages in said motor, said transfer member having a fluid tight engagement with said hub and motor and including adjustable means engaging said motor for axially adjusting said transfer member and said blade to preload said blade bearings.

2. In a propeller having a hub, a blade mounted for pitch changing movement in said hub including ball bearing means interposed between said blade and hub, the combination of a fluid motor carried by said blade for varying thepitch thereof including an element fixing said blade and motor against relative movement of the latter in an outboard direction, high pressure and drain pressure fluid passages carried by said hub, and a fluid transfer unit having a fluid tight sealing engagement with said fluid motor and-said hub and providing fluid communication therebetween'including means adjustably connected to said unit and engaging said motor for imparting a force therethrough and to said blade to preload said bearing means.

3. In a propeller having a hub, a blade mounted for pitch changing movement in said hub including ball bearing means interposed betweensaid blade and hub, the combination of, a fluidmotor carried by said blade for varying the pitch thereof including an element fixing said blade and motor against relative movement of the latter in an outboard direction, high pressure and drain pressure fluid passages carried by said hub, a fluid transfer unit having a fluid tight sealing engagement with said fluid motor and said hub and pro viding fluid communication between said pump and said passages, and an adjustable member threaded to said unit and engaging said motor for forcing said blade in an outboard direction and preloading said bearing including an abutment engaging said motor.

4. In a propeller, a hub including a blade receiving socket, a propeller blade positioned in said socket for pitch changing movements, anti-friction bearing means interposed between said blade and socket for retaining said blade therein, means responsive to fluid under pressure for varying the pitch of said blade comprising a fluid motor positioned in said blade having fluid receiving passages therein, said motor including a supporting member engaging said blade, high pressure and drain pressure fluid conducting passages in said hub, and a fluid transfer member operatively engageable with said motor in two positions angularly displaced 180 including passage means interconnecting said hub passages and the passages in said motor, said transfer member engaging said hub and having abutment means adjustable thereon and engaging said motor for imparting a preloading force to said motor and blade in an outboard direction.

5. In a propeller according to claim 4 including means for fixing said transfer member in either H of said two positions comprising cooperating elements carried by said motor and said transfer member.

6. In a propeller, a hub including a blade receiving socket, a propeller blade positioned in said socket for pitch changing movements, bearing means interposed between said blade and socket for retaining said blade therein comprising integral cooperating races carried by said blade and socket, means responsive to fluid under pressure for varying the pitch of said blade comprising a fluid motor positioned coaxially in said blade having fluid receiving passages therein, said motor including a rotatable portion having a supporting member engaging said blade and a cooperating relatively non-rotatable portion fixed to said hub having a central recess along its axis, high pressure and drain pressure fluid conducting passages in said hub, and a fluid transfer member operatively positionable in said recess in two positions displaced angularly about its axis including passage means interconnecting said hub passages and the fluid receiving passages in said motor, said transfer member sealably engaging said hub and including abutment means adjustable thereon and engaging said rotatable motor portion for imparting a preload to said blade in an outboard direction.

7. A propeller according to claim 6 including cooperating lock means carried by said non-rotatable motor portion and said transfer unit for predeterminately defining said two positions.

8. In a variable pitch propeller comprising a hub, a blade receiving socket, a blade mounted for pitch changing movements in said socket, and bearing means for retaining said blade in said socket, the combination of, a fluid motor carried by said blade for varying the pitch thereof in any of two directions, means limiting the movement of said motor axially of said blade, passage means in said hub for conducting fluid under pressure, and a member engaging said motor and said hub and having a sealing engagement with said hub including means providing fluid communication between said passage means and said motor, said member including adjustable means engaging said motor for axially adjusting said member and said blade to preload said blade bearings.

EARL M. FRANKLAND.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,425,261 Murphy et a1 Aug. 5, 1947 2,462,932 Anderson Mar. 1, 1949 2,470,560 Hoover May 1'7, 1949 2,530,520 Hackethal et a1. Nov. 21, 1950 2,533,415 Anderson Dec. 12, 1950 FOREIGN PATENTS Number Country Date 486,614 Great Britain June 8, 1938 727,968 Germany Nov. 16, 1942 

